Reallocating partitions usage in Linux without formatting

Something that is not unusual to happen: you do a bad planning of your disk partitioning and at the end you find out that you have a partition that is nearly full and want to move a directory from that partition to a new disk. If you already have some experience with Linux and command line you will probably know how to safely do this from the same machine and without losing any data, but it may be something a little more difficult for less experienced users.

I recently found one of these users in a similar situation and this was the result of the answer I gave to him by e-mail, now published: